不同厚度Tl-2212薄膜的表面形貌及超导特性研究

采用直流磁控溅射法和后退火技术在蓝宝石基片上制备了Tl-2212超导薄膜,考察了Tl-2212薄膜的厚度对其形貌和超导特性的影响。实验结果表明,随着超导薄膜厚度增加,其表面形貌由致密平整的结构演化为片状晶体结构,临界转变温度Tc和临界电流密度Jc先增大后减小,微波表面电阻Rs先减小后增大。在退火的CeO2缓冲层上所制备的无裂纹薄膜的最大厚度达到600nm,并仍然具有良好的超导性能。

Study on the Surface Morphology and Superconducting Properties of Tl-2212 Films with Different Thicknesses

Tl-2212 high temperature superconducting (HTS) films were prepared on r-cut sapphire substrates buffered with CeO2 by dc magnetron sputtering technique and post-annealing process. The effects of various thicknesses of Tl-2212 films on their surface morphologies and superconducting properties were investigated. The results show that with increasing of the superconducting film thickness, the dense surface morphology evolves into flake-like crystal structure, the critical temperature Tc and critical current density Jc increase and then decrease, and the microwave surface resistance Rs decreases and then increases. The maximum thickness limitation of the crack-free Tl-2212 films, with CeO2 buffer layers annealed, reaches to 600 nm. The films possess excellent superconducting properties.